The sonographic findings in 200 patients who underwent concurrent transabdominal and transvaginal pelvic ultrasound were reviewed. The sonographic techniques were compared for image quality, completeness of anatomic detail depicted, and unique diagnostic information. Transvaginal image quality was better in 79%-87% of scans; transabdominal image quality was better in 3%-5% of scans; images of both techniques were equally good in 10%-18% of scans. The techniques provided equivalent diagnostic information in 60%-84% of cases. Transvaginal sonography was particularly helpful when exclusion of ectopic pregnancy was the clinical concern. Individual organs and fine structures were better seen transvaginally, but the regional survey offered by the transabdominal full-bladder approach remains necessary to provide anatomic orientation, particularly when the patient has not been studied previously.